Stabilizing apparatus



Oct. 10, 1950 R. F. HAYS, JR 2,524,793

STABILIZING APPARATUS Filed Jan. 15, 1946 Patented Oct. 10, 1950STABILIZING APPARATUS Robert F. Hays, Jr., Syosset, N. Y., assignor toThe Sperry Corporation, a corporation of Delaware Application January15, 1946, Serial No. 641,382

. Claims.

This invention relates to an apparatus for stabilizing an airborne lineof sight defining ap paratus and more particularly to an apparatus foreliminating the error in the line of sight due to roll and pitch of thesupporting aircraft.

A feature of the invention is the provision of an apparatus adaptedparticularly for the stabilization in space of the scanner axis of aradio bomb sight. The invention may be used also to stabilize the lineof sight defined by an optical system.

Bomb sights generally comprise a computing mechanism having an outputwhich displaces a line of sight defining device according to thecomputed sighting angle. Usually the line of sight defining device is apart of the bomb sight and. is stabilized by vertical and directionalgyroscopes associated with the bomb sight mechanism. In someapplications, particularly where a radar line of sight defining deviceis used, it is desirable to attach the sighting apparatus directly tothe framework of the airplane and to direct the device by remote controlfrom the outto novel features of the instrumentalities described hereinfor achieving the principal objects of the invention and to novelprinciples employed in those instrumentalities, whether or not thesefeatures and principles are used for the said principal objects or inthe said field.

The invention will now be described with the aid of the accompanyingdrawings, of which Fig. 1 shows schematicall one form of the inventionas stabilizing the entrance prism of a periscope, while Figs. 2 and 3show schematically an arrangement for stabilizing a scanning device ofthe radar type.

In a preferred embodiment of the invention it is contemplated that thesighting angle be obtained as a shaft rotation from a. suitable bombsight, not shown, while the azimuth angle may be obtained as a shaftrotation from a directional gyroscope, not shown, which may be thedirecthe aircraft. The line of sight defining device is supportedindependentl of the bomb sight, and is positioned in sighting angle bythe bomb sight, and in azimuth by the directional gyro scope. Thepresent invention provides further means for adjusting the line of sightdefining device according to the sighting angle and in azimuth tocompensate for rolling and pitching of the aircraft.

The stabilizing mechanism of the present invention comprises a turntableIll supported for rotation in azimuth by any suitable means, such as thetrack H attached to the aircraft. The turntable is positioned in azimuthin accordance with the heading of the aircraft by a shaft l2 controlledby a directional gyro, not shown, the shaft being provided with a worml3 which meshes with teeth formed in the edge of the turntable.

A bracket l5 attached to the turntable is formed with a pair of uprightarms l6 and ll, the latter having horizontal arms l8 and I9 fixedthereto provided with bearings for shafts 2B and 21 attached to gimbalring 22 of a vertical gyroscope enclosed in casing 23. A spindle 24secured to the underside of gyro casing 23 in alignment with the spinaxis extends through a slot 25 in a bail 26. Opposite ends of the bailare fixed respectively to shafts 21 and 28 which are supported inbearings in arms l6 and I1 at right angles to shafts 20 and 2|.

It will be understood that erecting means of any suitable type, notshown, will be used to maintain the gyroscope erect. The roll axis ofthe gyroscope coincides with the axes of shafts 21 and 28 which are sodisposed as to follow the line of sight in azimuth, while shafts 2G and2| are disposed along the pitch axis. Since the gyroscope will remainvertical in space, movement of the aircraft in roll and pitch will causecorresponding movement of the shafts 2t and 2| and 21 and 28 in theirbearings.

Armature 30 of an E pickoff transformer 3| of conventional type isattached to shaft 2|. Displacement of the aircraft about the pitch axiscauses relative movement of the armature and transformer in the knownmanner, and the transformer, which is energized constantly from a sourceof alternating current supplies on such displacement, a signalcorresponding to the displacement, to the input of a. differential servoamplifier 32 provided with output circuits which control in the knownmanner a pitch servomotor 33. Servomotor 33 controls a follow-up systemwhich moves pickofi transformer 3| in such direction as to bring thetransformer again into register with its armature 39 and thus reduce theoutput signal therefrom to zero caus ing the motor to stop. Thefollow-up mechanism is used in conjunction with a sighting angle inputto position la. cam arrangement in one dimension, wh ich will bedescribed presently.

An armature 40 of a .pickoff transformer 4| for the roll axis isattached to shaft '28. Movement of the aircraft about the roll axiscauses relative displacement of the armature and trans former. Thetransformer is energized in the known manner from a source ofalternating current, and relative displacement of the armature causes asignal corresponding to the displacement to be transmitted from thetransformer to a. differential amplifier 42, which, in response to suchsignal, actuates a servomotor 43' Whichop- I erates a follow-upmechanism in such direction as to bring transformer into register withits armature. This follow-up mechanism cooperates with the azimuth servoshaft to effect relative displacement of the cam arrangement mentionedabove, and the lift pins therefor in another dimension, to be described.

Shaft 44, in the present embodiment of the invention is displaced inrotation according to the sighting angle, in the known manner, by a bombsight not shown. The object of the invention is to stabilize a sightingdevice controlled by this shaft. Shaft 44 actuates an input shaft for adifferential 45 which has a second input shaft 46 fastened to bracket l5so as to be turned with turntable ID to prevent azimuth rotation fromintroducing an error into the sighting angle.

three dimension cams 62 and 63 are fixed. The

cams are provided respectively with lift pins 64 and 65 which aremounted for translation with respect to the axis of the cams. The liftpins are supported in bearings at opposite ends of a bar 66 provided onone side with a rack, not shown, which is engaged by the teeth of a gear61 on a shaft 68 supported in a bearing in a bracket 69. Shaft 68 isturned by the roll servomotor 43. Shaft 68 also drives via gears 10,shaft ll, gears 12, shaft 13, a worm 14 which adjusts the position ofpickoff transformer 4| for the roll axis. It will be understood that anysuitable means may be used for guiding bar 66 when translated.

Lift pin 64 has a circular rack 80 formed thereon which is in mesh withthe teeth of a long pinion 8! on shaft 82 which drives through gears 83the input shaft 84 of differential 6B. Cam 62, therefore, is effectiveto displace input shaft 84, and output shaft 6| of the differential isdisplaced according, to the displacement of the pitch follow-up motor 33and the displacement of lift pin 64. A gear 85 secured at the lower endof shaft 6i drives a gear 86 fastened to shaft 81 which turns in abearing in bracket 69. 81, asshown in Fig. 1, displaces through gears 88a horizontal shaft 89 attached to prism 90 which may be the entranceprism of an optical system.

Lift .pin 65 has a circular rack 9! formed there-;

Shaft on which meshes with the teeth of long pinion 92 fastened to shaft93which turns in a bearing in bracket 69. Pinion 94 secured to shaft 93drives a rin gear 95 supported for rotation by turntable II] about aconcentric opening therein.

A tubular bracket arrangement 96 in which the horizontal shaft 89 forprism is supported, depends from the ring gear 95. Bracket 96 may be ofany convenient shape and may have any necessary openings formed thereinin accordance with the requirements of the optical system with which theprism is to be used. An eyepiece 91 of an optical system including theprism 90 is shown diagrammatically in Fig. 1. Equivalent mechanisms areshown in Figs. 2 and 3 for operating a radar scanner.

Bracket 96, together with-prism 90, are turned directly in azimuth bylift pin '65. The displacement-of the lift pin depends on cam 63 whichis actuated in rotation by shaft 6|, as already described. The movementof the lift pin axially of the cam depends on the displacement of theroll servomotor 43.

The displacement of shaft 6| depends on the pitch angle of the aircraftas indicatedby the gyroscope, the sighting angle, and the displacementof lift pin 64 by cam 62.

Lift pins 64 and 65 are translated along the axes of the cams inaccordance with the roll angle of the aircraft as indicated by thegyroscope. Cams 62 and 63 may be laid out empirically by graphicalprocedure to effect such displacement of their lift pins as to cause theline of sight to be constantly positioned at the correct angleirrespective of the roll and pitch of the airplane.

In a preferred form of the invention wherein, as mentioned above, theroll axis .of the gyroscope follows the line of sight in azimuth, thecorrections required for the sighting and azimuth angles of a radarscanner, or .other line of sight defining device are givenapproximatelyby the following equations:

sin A13=cot 18s (l-cos and sin Aa=COt 5s sin where Aa=azimuth correctionangle to be applied to the scanner;

Afi=sighting angle correction to be applied to the scanner;

=roll indicated by the gyro;

Bs=the angle between the line of sight to the target and the apparentvertical, i. e., a line perpendicular to the floor of the aircraft.

Both sin Ap and sin Ac are equal approximately to cot 3s multipliedrespectively by suitable functions of and cams actuated as describedabove may be laid out to provide output displacements according to Auand A5.

Bracket 96 is shown in Fig. 2 as having a pair of depending arms I02supporting horizontal shaft 89, which in this figure is shown ascarrying a parabola I 93 of a radar line of sight defining deviceinstead of prism 99 of Fig. 1.

The stabilizing arrangement of the present invention ma be used tostabilize a line of sight device by remote control. This feature isadvantageous, particularly where a radar scanner is mounted in the wingof a small airplane. Bracket 96 and shaft 81 are outputs for the deviceand they may be used to position, through any suitable connections aremotely located line of sight defining device. For this purpose;bracket 96, Fig. 1, may be provided with an annular gear I05 which turnsa flexible outputshaft .lllllto 5 actuate the arrangement shown in Fig.3, where shaft I00 is shown as being coupled with a parabola I03 to turnthe same about a vertical axis. In Fig. 3, shaft 81 is represented as aflexible shaft for positioning parabola I03 about a horizontal axis.

As many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description r shown in the accompanying drawingshall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In an apparatus for stabilizing the line of sight of a radar antennacarried by an aircraft, a pair of three dimension cams laid outrespectively to compute corrections for the position of the aircraft inroll and in pitch, individual lift pins for the cams, means responsiveto the roll and pitch of the aircraft for positioning the cams, andmeans controlled by the lift pins for adjusting the position of theantenna.

2. In an apparatus for stabilizing the line of sight of a radar antennacarried by an aircraft, sighting angle and azimuth position inputs, acomputing device comprising a pair of cams laid out to computecorrections for the position of the aircraft in roll and pitch, meansresponsive to roll and pitch of the aircraft and controlled by saidinputs for adjusting the position of the cams, and output means for thecams for adjusting the position of the antenna.

3. An arrangement for. stabilizing the sighting angle of a sight carriedby an aircraft comprising a vertical gyro having its roll axismaintained in alignment in azimuth with the line of sight of the sight,a sighting angle input, a device comprising a cam shaft jointlycontrolled by the sighting angle input and by the gyro according to thedisplacement of the aircraft about the pitch axis of the gyro forpositioning the line of sight according to the sighting angle, cam meansfor computing pitch correction actuated by the device and an output forthe last mentioned means coupled with the device effective to modify theposition of the line of sight according to the displacement of theaircraft in pitch.

4. An arrangement for stabilizing the sighting angle of a sight carriedby an aircraft comprising a vertical gyro having its roll axismaintained in alignment in azimuth with the line of sight of the sight,a sighting angle input, a shaft, means jointly displacing said shaft bythe sighting angle input and by the gyro according to the displacementof the aircraft with respect to the pitch axis of the gyro, adifferential having an input displaced by the shaft, an output therefor,a cam laid out to provide pitch correction actuated by the shaft in onedimension, a lift pin for the cam, means for producing relativedisplacement of the lift pin and cam in another dimension controlled bythe gyro according to displacement of the aircraft about the roll axisof the gyro, means controlled by the output of the differential fordisplacing the line of sight in one dimension and means controlled bythe lift pin for actuating a second input of the differential to modifythe displacement of the line of sight according to pitch correction.

5. An arrangement for stabilizing the sighting angle of a sight carriedby an aircraft comprising a member maintained positioned in azimuth, avertical gyro supported thereby, a sighting angle input, a differentialdevice having inputs controlled respectively by the sighting angle inputand by the gyro according to the displacement of the aircraft in pitch,an output for the differential for displacing the sight according to thesighting angle, pitch correction computing means actuated by thedifferential output, and an output for the computing means coupled withan input of the differential device for correcting the latter for pitcherror.

i 6. An arrangement for stabilizing the sighting angle of a sightcarried by an aircraft comprising a member maintained positioned inazimuth, a vertical gyro supported thereby, a sighting angle input, adifferential device having inputs controlled respectively by thesighting angle input and by the gyro according to the displacement ofthe aircraft in pitch, an output for the differential for displacing thesight according to the sighting angle, pitch angle correction computingmeans actuated by the differential output and by the gyroscope accordingto the displacement of the aircraft in roll and an output for thecomputing means coupled with the input of the differential deviceeffective to correct the output of the latter for displacement of theaircraft in pitch.

7. In an apparatus for stabilizing the line of sight of a sight carriedby an aircraft, a vertical gyro, a computing device comprising a pair ofcam's laid out respectively to compute corrections for pitch and rollerror, a lift pin for each cam, sighting angle and azimuth inputs, meanscontrolled by the inputs and by the gyro according to the displacementof the aircraft about one axis thereof for effecting relativedisplacement of the cams and lift pins in one dimension, meanscontrolled by the gyro according to the displacement of the aircraftabout another axis thereof for effecting relative displacement of thecams and lift pins in another dimension, and means adjusted by therespective lift pins for displacing the sight in two dimensions.

8. An apparatus for stabilizing automatically the line of sight of anairborne bomb sight against roll and pitch of a supporting aircraftwherein the line of sight is defined by a sighting device displaced byremote control from a bomb sight computer in accordance with thecomputed sighting angle and the azimuth angle thereof, said apparatuscomprising a turn table, a line of sight defining device supportedthereby for relative movement about two axes, one of which is coincidentwith that of the turntable, an input shaft for adjusting the turntablein accordance with the azimuth angle of the line of sight, a gyrovertical positioned on the turntable with its roll axis disposed alongthe line of sight in azimuth, a cam shaft, a pair of three dimensionalcams fixed thereon laid out respectively to compute corrections for thesighting angle and for the azimuth angle thereof, a lift pin for eachcam, means actuated by the gyro in accordance with the displacement ofthe aircraft about its roll axis for effecting relative displacement intranslation of the lift pins and cams, means operated by'the lift pin ofone of the cams for effecting relative coaxial movement of the line ofsight and turntable, a sighting angle input shaft, means including aplurality of differential devices jointly actuated by the lift pin ofthe other of the cams, the sighting angle input shaft and the gyroaccording to the displacement of the aircraft about its pitch axis forturning the cam shaft, and means actuated by .-.the camshaft fordisplacingthe line of sight defining device about another axis.

9. An apparatus for stabilizing the line of sight of a bombsight againstroll and pitch of the supporting aircraft which comprises a turntable, aline of sight defining device supported thereby for relative movementabout two axes, a first of which coincides with that of the turntable,an input shaft for turning the turntable according to the azimuth angleof the line of sight, a gyro vertical positioned on the turntable withits roll axis disposed along the line of sight in azimuth, a camshaftmounted on the turntable, a pair of three dimensional cams fixed thereonlaid out respectively to compute corrections for the sighting angle andazimuth angle, a lift pin for each cam, means actuated by the gyroaccording to displacement of the aircraft about its roll axis foreffecting relative displacement of the cams and lift pins :intranslation, means operated by the lift pin of one of the cams foreffecting relative coaxial movement of the line of sight defining deviceand turntable according to the required correction for the azimuthangle, a sight- ,sight of a bomb sight against roll and pitch of thesupporting aircraft which comprises a turn .tablemounted. on theaircraft, a line of sight defining device supported thereby for relativemovement about two axes, aninput shaftfor turning the turntableaccording to the azimuth angle of the line ofsight, a gyro verticalpositioned on the turntable so that its roll axis follows the azimuthangle of th line of sight, a cam shaft supported for rotation on theturntable, a pair of three dimensional camsfixed thereto, -a first ofthe cams being laid out to provide corrections for the sighting angleand the second of the cams being laid out to provide corrections for thazimuth angle thereof, a lift pin for each cam, means actuatedby thegyro according to the displacement of the aircraft about its roll axisfor displacing the lift pins in translation with respect tothe cam's,-means operated by-the lift pin of the second of the cams for turningthe line of sight defining device about one axis to correct the azimuthangle thereof, a sighting angle inputshaft, means including a pluralityof differential devices jointly actuated by the lift pin of the firstcam, the sighting angle input shaft and the gyro according to thedisplacement of the aircraft about its pitch axis for rotatin the camshaft, and means driven by the cam shaft for adjusting the line of sightabout a second axis in accordance with the-sighting angle.

11. An apparatus for stabilizing the line of sight of a bomb sightagainst roll and .pitch of the supporting aircraft which comprises aturntable mounted on the aircraft, a line of sight defining devicesupported thereby for relative movement about two axes, one of whichcoincides with that of the turntable, an input shaft for turning theturntable according to thecomputed iazimuth angle of the line of sight,a gyro vertical fixed to theturntable withits roll axis disposed in thevertical plane which includes the line of sight in azimuth, a cam shaftmounted on the turntable, a pair of three dimensional cams fixedthereto, a first of the cams being laid-out to compute corrections forthe sighting angle and the second cam being laid out to providecorrections for the azimuth angle thereof, a lift .pin for each cam,means actuated by the gyro according to the displacement of the aircraftabout the roll axis thereof for translating the lift pins along thesurfaces of the cams, means including shafts and gearing actuated by thelift pin of the second cam for adjusting the angular position of thesighting device about the axis coincident with that of the-turntable. tocorrect the azimuth angle thereof, a sighting angle input shaft, meansincluding a plurality of differential mechanisms operated jointly by thelift pin of the first cam, the sighting angle input shaft and the gyroin accordance with the displacement of the aircraft about the pitch axisthereof for turning the cam shaft, and means comprising shafts and gearscoupling the cam shaft with the sighting device for adjusting theangular position thereof about a second axis according to the sightingangle.

12. An apparatus for stabilizing automatically the line of sight of anairborne bomb sight antenna against roll and pitch of a supportingaircraft wherein the antenna is positioned angularly about twointersecting axes by remote control from a bomb sight computer inaccordance with a computed sighting angle and the azimuth thereof, saidapparatus comprising a turntable, an input shaft for rotating theturntable in accordance with the azimuth angle of the line of sight, agyro vertical mounted on the turntable with its roll axis disposed alongthe line of sight in azimuth, a cam shaft, a pair of three dimensionalcams thereon laid out respectively to compute corrections for thesighting angle and the azimuth angle thereof, a lift pin for each cam,means actuated by the gyro in accordance with the displacement of theaircraft about the roll axis thereof for effecting relative displacementin translation of the lift pins and cams, means operated by the lift pinof the one of the cams for adjusting the angular position of the antennaabout one of its axes, a sighting angle input shaft, means including aplurality of cooperating differential mechanisms jointly actuated by thelift pin of the other of the cams, the sighting angle input shaft andthe gyro in accordance with the displacement of the aircraft about thepitch axis thereof for turning the cam shaft, and means driven from thecam shaft for adjusting the angular position of the antenna about theother of its axes.

13. An apparatus for stabilizing automatically the line of sight of anairborne radar antenna of the kind which is movable about twointersecting axes under control of a remote computer in accordance witha computed sighting angle and the azimuth angle thereof, which comprisesa turntable mounted on the supporting aircraft, a gyro verticalsupported, thereby, an input shaft for turning the turntable to causethe roll axis of the gyro to follow the line of sight in azimuth, a camshaft mounted on-the turntable, a pair of three dimensional cams fixedthereon laid out respectively to compute corrections for the sightingangle and azimuth angle to compensate for roll and pitch of thesupporting aircraft, a lift pin for each cam, means actuated by the gyroin accordance with the displacement of the aircraft about the roll axisthereof for effecting relative displacement of the cams and lift pinsintranslation, means operated by the lift pin of one of the cams foreffecting displacement of the antenna about one of its axes inaccordance with the corrected azimuth angle, a sighting angle inputshaft, means including a plurality of cooperating differential devicesjointly actuated by the lift pin of the other of the cams, the sightingangle input shaft and the gyro in accordance with the displacement ofthe aircraft about the pitch axis thereof for turning the cam shaft, andmeans actuated by the cam shaft for displacing the antenna about theother of its axes in accordance with the corrected sighting angle.

14. In an apparatus for stabilizing a radar antenna mounted on anaircraft against roll and pitch, the antenna being of the kind adaptedfor operation by remote control from a computer which displaces theantenna about two intersecting axes respectively in accordance with acomputed sighting angle and the azimuth angle thereof, the improvementwhich comprises a turntable mounted on the supporting aircraft, a gyrovertical supported on the turntable, an input shaft for turning theturntable to keep the roll axis of the gyro in alignment with the lineof sight in azimuth, a radar antenna mounted for movement about two axeson the under side of the turntable, one of the axes being coincidentwith that of the turntable, a cam shaft mounted on the turntable, a pairof three dimensional cams fixed thereto, a first cam being laid out tocompute c0rrections for the azimuth angle of the line of sight, thesecond cam being laid out to compute corrections for the sighting angle,a lift pin for each cam, means actuated by the gyro in accordance withthe displacement of the aircraft about the roll axis thereof foreffecting relative displacement of the cams and lift pins in translation, means operated by the lift pin of the first of the cams foreffecting relative displacement of the antenna and turntable inaccordance with the corrected azimuth angle, a sighting angle inputshaft, means including a plurality of cooperating differentialdevices'jointly actuated by the lift pin of the second of the cams, thesighting angle input shaft, and the gyro in accordance with thedisplacement of the aircraft about the pitch axis thereof for turningthe cam shaft, and means actuated by the cam shaft for displacing theantenna about the other of its axes in accordance with the correctedsighting angle.

15. In an apparatus for stabilizing a radar antenna mounted on anaircraft against roll and pitch, wherein the antenna is of the type usedin conjuction with a remotely located bomb sight computer whichdisplaces the antenna about two intersecting axes in accordance with thesighting angle and the azimuth angle thereof respectively, theimprovement which comprises a turntable mounted on the supportingaircraft, a gyro vertical supported on the turntable, an input shaft forturning the turntable to maintain the roll axis of the gyro in alignmentwith the sighting angle in azimuth, a radar antenna mounted on the underside of the turntable for movement about two intersecting axes one ofwhich coincides with that of the turntable and the other being disposedat right angles thereto, a cam shaft mounted on the turntable, a pair ofthree dimensional cams fixed thereto, a first of the cams being laid outto compute corrections for the azimuth angle of the line of sight, thesecond cam being laid out to compute corrections for the sightin angle,a lift pin for each cam, means actuated by the gyro in accordance withthe displacement of the aircraft about the roll axis thereof fortranslating both cam pins along the surfaces of the cams, means operatedby the lift pin of the first of the cams for effecting relativedisplacement of the antenna with respect to the turntable about theircoincident axes in accordance with the corrected azimuth angle, asighting angle input shaft, means including a plurality of cooperatingdifferential mechanisms jointly actuated by the lift pin of the secondcam, the sighting angle input shaft, and the gyro in accordance with thedisplacement of the aircraft about the pitch axis thereof for turningthe cam shaft, and means actuated by the cam shaft for displacing theantenna about the other of its axes in accordance with the correctedsighting angle.

ROBERT F. HAYS, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,733,531 Dugan Oct. 29, 19291,937,336 Ford et a1 Nov. 28, 1933 2,371,606 Chafee et a1 Mar. 20, 19452,407,275 Hays Sept. 10, 1946 2,415,680 Hoyt Feb. 11, 1947

